Hybrid inheritance

#include<iostream.h>
#include<conio.h>
class A
{
public:
int a;
void geta()
{
cout<<"Enter A: ";
cin>>a;
}
};
class B:public A
{
public:
int b;
void getb()
{
cout<<"Enter B: ";
cin>>b;
}
};
class D
{
public:
int sum;
};
class C:public D,public B
{
public:
void disp()
{
geta();
getb();
sum=a+b;
cout<<"A+B="<<sum;
}
};
void main()
{
C c;
clrscr();
c.disp();
getch();
}